Re: DMP XR-20 - NO DC

[Jim <alarminex@xxxxxxx>]

On Aug 17, 4:18=A0pm, "Bob La Londe" <n...@xxxxxxxx> wrote:
> I've got an XR-20 with no DC. =A0Well its about 2.8 volts. =A0Battery lea=
ds and
> Aux power both. =A0I see no fuse on the board anywhere, so I am guessing =
its
> got circuit breakers. =A0Any suggestions? =A0What gets me is AUX and Batt=
ery are
> both low/dead. =A0Most panels have separate fuses or circuit breakers for=
 the
> battery and Aux circuits.

I don't know what you've already tried so here's what first comes to
mind.

Bad rectifier? or the battery leads were reversed? ( I don't know how/
if they have breaker for reversed leads) If the transformer got a
blast etc............. might have taken out the rectifier.  If there's
no breaker .... settable or self resetting ....... are there any
permanent fuses on the board or on the back of the board?

If you can find the rectifier, measure the DC output. It's going to be
unregulated so if you have an analog meter, it'll allow you to better
guess at the average output. If it is the rectifier you can usually
replace it pretty easily or substitute four healthy diodes. Alarm
mfg's pretty much use compressed mud for components. Don't know how
much you get into circuitry but sometimes the rectifier is good but
the regulation components are bad. Capacitor or Zener diode ( if they
still use them anymore). If you can find the regulation components,
measure on the other side of them to see if you get better DC. If it's
all good up to that point then ....

If there are breakers and you get a good DC reading after the
rectifier it could be a bad breaker. You'd have to follow the DC out
from the rectifier to each of the breakers. Not too easy to do. A
partial voltage reading could be indication of a bad (not resetting)
breaker. But since more than one voltage output is bad, it doesn't
seem like they'd use one breaker for all of them.

Did you check the back of the board for a burned conductor?

If you have another working board, you can use it to get comparison
voltage readings to determine where it differs.

Or ..... you could just throw it in the garbage and buy another
board ....  :-)